Manure treatment system erases greenhouse gases

Linda Tokarz, United States Department of Agriculture | May 17, 2007

Less greenhouse gas — and more carbon credits per pig — are the latest environment-friendly benefits being credited to an innovative hog waste-management system invented by Agricultural Research Service (ARS) scientists.

The system was introduced in 2004 by soil scientists Matias Vanotti, Ariel Szögi and Patrick Hunt at the ARS Coastal Plains Soil, Water and Plant Research Center, Florence, S.C., and their colleagues. It's being called the "Super Soil System," after Super Soil Systems USA Inc., a North Carolina fiirm that implemented and is marketing it.

It turns hog waste into material for soil amendments and fertilizers, while removing almost all suspended solids, phosphorus and ammonia from the wastewater.

In the latest research — conducted at the large North Carolina hog-finishing operation that hosted initial system testing three years ago — the ARS researchers found that replacing conventional anaerobic lagoon practices with the new system reduced greenhouse gas emissions by 97 percent.

It cut annual emissions from 4,972 tons of carbon dioxide equivalents to just 153 tons. This indicates the system may have a role in the fledgling CO2 trading market, which allows farmers to earn money based on how much carbon dioxide and other greenhouse gases they can prevent from entering the atmosphere using alternative technologies.

Seen in this fashion, the Super Soil System lets hog producers garner more carbon credits per pig than the technology commonly used today does, according to Vanotti. Szögi noted that earned carbon credits can help alleviate installation costs associated with cleaner aerobic systems.

Full-scale demonstration of the system — the only on-farm technology certified in North Carolina to replace anaerobic lagoons — was made possible through agreements with North Carolina's Attorney General's office, Smithfield Foods, Inc., and Premium Standard Farms.

The full-scale implementation of a lower-cost version of the system is currently going exceptionally well, according to Vanotti.

ARS is the U.S. Department of Agriculture's chief scientific research agency.